1. Field of the Invention
The present invention relates to a starter motor and accompanying gear mechanism for cranking an internal combustion engine, such as a reciprocating internal combustion engine.
2. Disclosure Information
Internal combustion engines, particularly automotive internal combustion engines, have been equipped with electric self-starters since pioneering work by Charles Kettering led to the first automotive self-starter in 1912. As typically applied to automotive internal combustion engines, and, for that matter to most internal combustion engines, the self-starter uses a large diameter ring gear and a starter motor having an axis which is generally parallel to the engine's crankshaft. The starter motor is equipped with a spur gear that is driven into contact with the flywheel/ring gear by means of a solenoid. Unfortunately, conventional starters are noisy for a variety of reasons. First, the gears are unlubricated. As another source of noise, the gears are generally not enclosed within a case that is capable of muting sound generated by the gears.
A more troublesome drawback to present starting systems using large diameter ring gears is that the profile of the engine is adversely affected (e.g., made overly large). This presents a problem to vehicle designers because a large diameter ring gear prevents the engine from being moved farther down in a vehicle, thereby inhibiting efforts to produce more aerodynamic, fuel efficient vehicles.
A starter system according to the present invention uses a worm gear and worm drive system, including an input gear which is journaled for rotation, including relative rotation, to the engine's crankshaft. U.S. Pat. No. 6,758,181 discloses a worm gear starter system which, although being useful for a small one cylinder engine, as witnessed by the fact that the starter of the '181 patent has a rope handle, as well as an electro-drive, is not useful for an automotive engine because it must be cantilevered from one end of the engine, and is therefore not amenable to packaging within an automotive engine requiring a front-end accessory drive, nor would it be expected to exhibit the durability characteristics needed for an automotive engine starter system.